The invention relates to a lens assembly.
When mounting a lens into a lens barrel to fix it therein, the barrel is either internally or externally threaded and is threadably engaged by a retaining ring, which is tightened to a suitable degree to fix the lens by bearing against a peripheral region thereof. Unless the ring bears against the lens with a uniform force throughout the lens periphery, the lens may be oblique relative to the barrel. This may prevent a firm fixing, or a distortion may be produced in the lens as a result of greater force being applied to one part of the lens periphery than to the rest thereof, causing the performance of the lens system to be degraded. To prevent such degradation, both the barrel and the ring must be threaded or tapped in a positive manner so that the ring bears against the lens with a uniform force. However, performing a tapping operation with sufficient accuracy or tightening the retaining ring with a suitable pressure is a troublesome operation which requires a number of operating steps.